Intermodal containers are commonly used when shipping goods domestically and/or internationally. Such containers can be loaded onto cargo ships for transport across oceans or other bodies of water. For land transport, these containers can be placed onto a trailer and then hauled overland by truck. Such containers can also be loaded onto railroad flatcars for transport.
Shipping containers can be loaded with boxes, crates, drums, reinforced bags, plastic wrapped bundles, cased goods, metal coils, specialty heavy paper rolls, plastic or metal containers mounted on pallets, and/or numerous other forms of cargo. Maritime and surface transportation regulations require that such loads be restrained from lateral shifting. In particular, a shipping container may experience significant movement as the container is carried by ocean vessel or by other conveyance. If cargo within the intermodal container is not restrained, it may shift and collide with a container wall or container doors. Because the mass of cargo in a container can be significant, such shifting and/or collisions can have catastrophic consequences for transport workers and for the public at large. For example, shifting cargo can be damaged when colliding with a container wall and/or be crushed by other shifting cargo. Damaged cargo can lead to release of product, which product may be toxic or otherwise be hazardous. As another example, shifting cargo might change the center of gravity of the shipping container itself and thereby cause significant problems for the ship, truck or other vehicle carrying the container.
FIG. 1 illustrates a known technique for restraining cargo within a shipping container 101. A portion of a top 103 and right side wall 102R have been cut away from container 101 to reveal cargo loaded therein. In the example of FIG. 1, the cargo includes a load of crates 104 and drums 105. FIG. 1 further shows a portion of an interior of a left side wall 102L. Crates 104 and drums 105 are secured against movement toward the rear 111 of container 101 by a restraint system that includes multiple restraining strips 106. Each strip 106 is flexible and has an adhesive-coated end 107. An end 107a of a first strip 106a is pressed against an interior surface of side wall 102R. The other end 108a of strip 106a is then wrapped around the rear of a portion of crates 104. Strip end 107a and other strip ends in FIG. 1 are stippled to indicate the presence of adhesive; the stippling in FIG. 1 is not intended to indicate a color differential.
A second strip 106b is similar to strip 106a and has an adhesive-coated end (not shown) similar to end 107a of strip 106a. The adhesive-coated end of strip 106b is secured to the interior surface of side wall 102L in a position that is at generally the same height as end 107a. The end 108b of the strip 106b is then wrapped around the rear of the portion of crates 104 similar to end 108a. Ends 108a and 108b are then tightened (e.g., using a tool and method such as is described in U.S. Pat. No. 6,981,827, incorporated by reference herein). A third adhesive-backed strip 109 is then applied over the tightened ends 108a and 108b to secure those ends together. In a similar manner, strips 106c and 106d and other pairs of strips 106 are used to secure crates 104 and drums 105 from lateral movement.
There are various types of known restraining strips that can be used in the configuration of FIG. 1. Such strips typically include a backing and some form of reinforcement. Examples of known strips are described in one or more of U.S. Pat. Nos. 6,089,802, 6,227,779, 6,607,337, 6,896,459, 6,923,609, 7,018,151, 7,066,698, 7,290,969, 7,329,074, 8,113,752, 8,128,324, 8,403,607, 8,403,608, 8,403,609, 8,408,852 and 8,419,329. Use of these and other types of restraining strips such as is shown in FIG. 1 represents a substantial improvement over previous methods for restraining cargo. However, improvement in the adhesion of the restraining strips under load, as well as a reduction in the number of strips required to secure a load would be advantageous.
For example, although cargo may be restrained, it often imposes severe forces on a load restraint system during transport. For example, a container may abruptly decelerate (e.g., in response to a sudden stop of a vehicle carrying the container) or accelerate (e.g., in response to sudden movement of the vehicle). As another example, a large portion of cargo weight may be supported by a load restraint system if a container is tilted from the horizontal (e.g., on a rolling ship at sea). Such forces imposed on a load restraint system by the cargo may stress the adhesive used to affix the load restraint strips to the wall of the cargo container. In some examples, the stress may overcome the adhesive bond and the strip may pull away or peel back from the wall.
Further, cargo containers are often loaded in a high throughput environment. In other words, it is often the case that numerous containers must be loaded as quickly as possible. In the case of Department of Defense shipments, for example, container stuffing and mobilization speed is of extreme logistical and tactical importance. It is thus advantageous to minimize the amount of time needed to load each container. Attaching load restraint strips (or other type of securement system) accounts for a significant amount of the time needed to load each container.